In the Notification settings there are 3 sub screens for events, tasks and birthday notifications.
Furthermore there is the new Sticky Date feature, which puts the date into the status bar and indicated the next few events.
Last, you see a TEST button, which creates a test notification and performs several checks for common setup issues that interfere with notifications.
To configure the default notifications for new timed and all-day events, please go to Event defaults and Editor settings.
The insistent option was removed by Google for Android 8 which now is mandatory for all new and updated apps. We plan to add a re-notify feature soon.
For further info please also see notifications.